J. Bush, C. A. Davis, P. Davis, A. Cekorich, Fred P. McNair
A novel design approach for a highly reliable buried intrusion detection sensor is described. The design involves the use of a low cost depolarized Sagnac fiber interferometer with a 'sensing loop' consisting of a delay line and buried fiber segment. The intrusion sensor is configured for an 'all fiber' remote deployment where active components (source, receiver, demodulator) are located separately and connected to the sensor through an insensitive fiber tether. A robust and cost effective buried sensor 'mat' design was developed. This design enabled high sensitivity as well as ease of deployment. Sensors were built and evaluated. Test results indicate an effective design.
{"title":"Buried fiber intrusion detection sensor with minimal false alarm rates","authors":"J. Bush, C. A. Davis, P. Davis, A. Cekorich, Fred P. McNair","doi":"10.1117/12.323429","DOIUrl":"https://doi.org/10.1117/12.323429","url":null,"abstract":"A novel design approach for a highly reliable buried intrusion detection sensor is described. The design involves the use of a low cost depolarized Sagnac fiber interferometer with a 'sensing loop' consisting of a delay line and buried fiber segment. The intrusion sensor is configured for an 'all fiber' remote deployment where active components (source, receiver, demodulator) are located separately and connected to the sensor through an insensitive fiber tether. A robust and cost effective buried sensor 'mat' design was developed. This design enabled high sensitivity as well as ease of deployment. Sensors were built and evaluated. Test results indicate an effective design.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115239010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The security of civil engineering works demands a periodical monitoring of the structures. The current methods (such as triangulation, water levels, vibrating strings or mechanical extensometers) are often of tedious application and require the intervention of specialized operators. The resulting complexity and costs limit the frequency of these measurements. The obtained spatial resolution is in general low and only the presence of anomalies in the global behavior urges a deeper and more precise evaluation. There is therefore a real need for a tool allowing an automatic and permanent monitoring from within the structure itself and with high precision and good spatial resolution. In many civil structures like bridges, tunnels and dams, the deformations are the most relevant parameter to be monitored in both short and long-terms. Strain monitoring gives only local information about the material behavior and too many such sensors would therefore be necessary to gain a complete understanding of the structure's behavior. We have found that fiber optic deformation sensors, with measurement bases of the order of one to a few meters, can give useful information both during the construction phases and in the long term. In the case of beams and bridges, long-gage sensors can be used to evaluate the curvature variations and calculate the horizontal and vertical displacements by double integration of the curvatures.
{"title":"Long-gauge structural monitoring for civil structures","authors":"D. Inaudi, Samuel Vurpillot, E. Udd","doi":"10.1117/12.323420","DOIUrl":"https://doi.org/10.1117/12.323420","url":null,"abstract":"The security of civil engineering works demands a periodical monitoring of the structures. The current methods (such as triangulation, water levels, vibrating strings or mechanical extensometers) are often of tedious application and require the intervention of specialized operators. The resulting complexity and costs limit the frequency of these measurements. The obtained spatial resolution is in general low and only the presence of anomalies in the global behavior urges a deeper and more precise evaluation. There is therefore a real need for a tool allowing an automatic and permanent monitoring from within the structure itself and with high precision and good spatial resolution. In many civil structures like bridges, tunnels and dams, the deformations are the most relevant parameter to be monitored in both short and long-terms. Strain monitoring gives only local information about the material behavior and too many such sensors would therefore be necessary to gain a complete understanding of the structure's behavior. We have found that fiber optic deformation sensors, with measurement bases of the order of one to a few meters, can give useful information both during the construction phases and in the long term. In the case of beams and bridges, long-gage sensors can be used to evaluate the curvature variations and calculate the horizontal and vertical displacements by double integration of the curvatures.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"3489 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129549174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A rugged telemetry system for coiled-tubing drilling and other hostile environment applications is briefly described. System performance before and after being tested in drilling operations (rotating, drilling, and reaming) was unchanged. However, in a laboratory test at 150 degrees Celsius, signal- to-noise ratio performance at higher carrier frequencies was degraded. Design improvements are also presented.
{"title":"Rugged telemetry system: testing results and design improvements","authors":"R. Weis, B. M. Beadle, B. L. Bachim","doi":"10.1117/12.323421","DOIUrl":"https://doi.org/10.1117/12.323421","url":null,"abstract":"A rugged telemetry system for coiled-tubing drilling and other hostile environment applications is briefly described. System performance before and after being tested in drilling operations (rotating, drilling, and reaming) was unchanged. However, in a laboratory test at 150 degrees Celsius, signal- to-noise ratio performance at higher carrier frequencies was degraded. Design improvements are also presented.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134277715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Early warning tool for chute failure in a sugar mill","authors":"S. Spammer, P. Swart, H. Loock","doi":"10.1117/12.323425","DOIUrl":"https://doi.org/10.1117/12.323425","url":null,"abstract":"Not Available","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125133379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Nelson, A. Makino, C. M. Lawrence, J. Seim, W. Schulz, E. Udd
A methodology is described for determining a relation (K- matrix) between wavelength shifts and (1) axial strain, (2) two transverse strains and (3) temperature change experienced by a multi-parameter Bragg grating sensor. The sensor is formed by writing gratings at two wavelengths in polarization maintaining fiber. The methodology is based on separate experimental calibrations of sensor response to transverse loading (diametral compression), axial loading and temperature changes. Strains produced in the core by the loadings or temperature changes used in the calibrations are determined by finite element analyses.
{"title":"Determination of the K-matrix for the multiparameter fiber grating sensor in AD072 fibercore fiber","authors":"D. Nelson, A. Makino, C. M. Lawrence, J. Seim, W. Schulz, E. Udd","doi":"10.1117/12.323418","DOIUrl":"https://doi.org/10.1117/12.323418","url":null,"abstract":"A methodology is described for determining a relation (K- matrix) between wavelength shifts and (1) axial strain, (2) two transverse strains and (3) temperature change experienced by a multi-parameter Bragg grating sensor. The sensor is formed by writing gratings at two wavelengths in polarization maintaining fiber. The methodology is based on separate experimental calibrations of sensor response to transverse loading (diametral compression), axial loading and temperature changes. Strains produced in the core by the loadings or temperature changes used in the calibrations are determined by finite element analyses.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128189239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes a novel fiber optic-based hydrogen sensor. The sensor consists of a thin-film etalon, constructed on the distal end of a fiber optic. The exterior mirror of the etalon is palladium or a palladium-alloy, which undergoes an optical change upon exposure to hydrogen. Data is presented on fiber optic sensors constructed with palladium and several alloys of palladium. The linearity of the optical response of these sensors to hydrogen is examined. Etalons made with pure palladium are found to be desirable for sensing low concentrations of hydrogen, or for one-time exposure to high concentrations of hydrogen. Etalons made from palladium alloys are found to be more desirable in applications were repeated cycling in high concentrations of hydrogen occurs.
{"title":"Fiber optic hydrogen sensor","authors":"C. Jung, E. Saaski, D. Mccrae","doi":"10.1117/12.323426","DOIUrl":"https://doi.org/10.1117/12.323426","url":null,"abstract":"This paper describes a novel fiber optic-based hydrogen sensor. The sensor consists of a thin-film etalon, constructed on the distal end of a fiber optic. The exterior mirror of the etalon is palladium or a palladium-alloy, which undergoes an optical change upon exposure to hydrogen. Data is presented on fiber optic sensors constructed with palladium and several alloys of palladium. The linearity of the optical response of these sensors to hydrogen is examined. Etalons made with pure palladium are found to be desirable for sensing low concentrations of hydrogen, or for one-time exposure to high concentrations of hydrogen. Etalons made from palladium alloys are found to be more desirable in applications were repeated cycling in high concentrations of hydrogen occurs.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125951923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of fiber optic sensors for the internal state measurements of large civil structures has been increasing in recent years. In many instances, sensors are embedded into the reinforced concrete structure is an attempt to measure a single parameter of interest. Installation and preliminary measurements obtained from a suite of fiber optic sensors which were embedded into a 67 m steel truss bridge spanning the Winooski River in Vermont (USA) are presented.
{"title":"Fiber optic sensors in the Waterbury Bridge","authors":"P. Fuhr, S. Spammer","doi":"10.1117/12.323424","DOIUrl":"https://doi.org/10.1117/12.323424","url":null,"abstract":"The use of fiber optic sensors for the internal state measurements of large civil structures has been increasing in recent years. In many instances, sensors are embedded into the reinforced concrete structure is an attempt to measure a single parameter of interest. Installation and preliminary measurements obtained from a suite of fiber optic sensors which were embedded into a 67 m steel truss bridge spanning the Winooski River in Vermont (USA) are presented.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131657752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Traditional methods of measuring surface tension and viscosity of liquid/vapor interface are invasive systems making unavoidable mechanical contact with the interface that is under investigation. We have demonstrated a complete fiber optics based heterodyne sensor system that non-invasively measures the interfacial surface tension and viscosity. Measured values from this complete fiber optics system for some simple liquid vapor interfaces give consistent values with established values obtained by other invasive methods.
{"title":"Noninvasive measurement of surface tension and viscosity with fiber optic light-scattering spectrometer","authors":"P. Tin, J. Mann, W. Meyer","doi":"10.1117/12.323423","DOIUrl":"https://doi.org/10.1117/12.323423","url":null,"abstract":"Traditional methods of measuring surface tension and viscosity of liquid/vapor interface are invasive systems making unavoidable mechanical contact with the interface that is under investigation. We have demonstrated a complete fiber optics based heterodyne sensor system that non-invasively measures the interfacial surface tension and viscosity. Measured values from this complete fiber optics system for some simple liquid vapor interfaces give consistent values with established values obtained by other invasive methods.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123841016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity. We have produced, using this scanning device, in vivo cross-sectional images of hard and soft dental tissues in human volunteers. Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento- enamel junction, were visible in all the images. The cemento- enamel junction and the alveolar bone were identified in approximately two thirds of the images. These images represent, or our knowledge, the first in vivo OCT images of human dental tissue.
{"title":"Fiber optic-based optical coherence tomography (OCT) for dental applications","authors":"M. Everett, B. Colston, L. D. Da Silva, L. Otis","doi":"10.1117/12.323431","DOIUrl":"https://doi.org/10.1117/12.323431","url":null,"abstract":"We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity. We have produced, using this scanning device, in vivo cross-sectional images of hard and soft dental tissues in human volunteers. Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento- enamel junction, were visible in all the images. The cemento- enamel junction and the alveolar bone were identified in approximately two thirds of the images. These images represent, or our knowledge, the first in vivo OCT images of human dental tissue.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121670809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Schulz, E. Udd, J. Seim, H. M. Laylor, G. Mcgill
There are approximately 576,000 major bridges, 3.2 billion square feet of bridge deck, and 162,000 miles of highways making up a part of the civil infrastructure system in the United States. Fiber grating strain sensors have the ability to play an important role in the health monitoring of these structures. The advantages of fiber optic sensors including EMI resistance, unobtrusive size, multiplexing/distributed capabilities, and environmental ruggedness, make them a logical choice for structural monitoring.
{"title":"Single- and multiaxis fiber-grating-based strain sensors for civil structure applications","authors":"W. Schulz, E. Udd, J. Seim, H. M. Laylor, G. Mcgill","doi":"10.1117/12.323417","DOIUrl":"https://doi.org/10.1117/12.323417","url":null,"abstract":"There are approximately 576,000 major bridges, 3.2 billion square feet of bridge deck, and 162,000 miles of highways making up a part of the civil infrastructure system in the United States. Fiber grating strain sensors have the ability to play an important role in the health monitoring of these structures. The advantages of fiber optic sensors including EMI resistance, unobtrusive size, multiplexing/distributed capabilities, and environmental ruggedness, make them a logical choice for structural monitoring.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127529915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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